Built-in Methods
The Big Idea
You already explored built-in methods in the Research JavaScript Methods task. Now you will apply them — writing real functions that use join, map, filter, find, and split to make tests pass. You do not need to memorise these methods — you need to know how to look them up and use them.
Your Roadmap
| Section | Time | Required? |
|---|---|---|
| Where to find the docs | 5 min | ⚑ Required |
| The functions to write | 4 hrs | ⚑ Required |
| Reflect | 10 min | ⚑ Required |
Where to find the docs
MDN lists every built-in method available for:
For each function below, research the method you need before writing your code.
The functions to write
concatMyArray
Takes an array of individual strings and joins them into one string.
Method to research: Array.join()
capitalize
Takes a sentence string. Returns the same sentence with the first letter of every word capitalised.
Methods to research: String.split(), Array.map(), String.toUpperCase()
whereAreYou
Takes an array of objects. Returns the first object that contains "Scooby".
Method to research: Array.find()
Look at the test file whereAreYou.test.js or use console.log inside the function to understand the shape of the data.
deBee
Takes a string. Splits it into individual words, then filters out every word that is "buzz". Returns the cleaned string.
Methods to research: String.split(), Array.filter()
Reflect
Navigate to your my-reflections-sprint-4 file and answer the question under the heading Kata.
Commit and push your changes to GitHub.